Related Experiment Videos
Partial amino acid sequence of rat pre-prolactin
Abstract:
Rat pituitary mRNA was used to direct the cell-free synthesis of pre-prolactin labelled with [4,5-3H]leucine and either [35S] methioninc or [35S] cystine. Sequence analysis of the labelled protein indicates that pre-prolactin has 29 amino acid residues joined to the N-terminus of the prolactin sequence. Leucine residues were found at positions 13, 14, 15, 16, 21 and 22, methionine residues at positions 1, 17 and 18, and a cysteine residue at position 24 of the precursor sequence, and this partial sequence shows considerable similarity with other precursors that have been sequenced.
Insights
Researchers synthesized and sequenced rat pre-prolactin, identifying a 29-amino acid N-terminal extension. This precursor sequence shows similarities to other known protein precursors, aiding in understanding protein processing.
Area of Science:
- Molecular Biology
- Biochemistry
- Endocrinology
Background:
- Prolactin is a key hormone regulating reproduction and lactation.
- Understanding prolactin precursor structure is crucial for deciphering its synthesis and regulation.
Purpose of the Study:
- To elucidate the N-terminal sequence of rat pre-prolactin.
- To analyze the structural features of the prolactin precursor.
Main Methods:
- Cell-free synthesis of rat pre-prolactin using pituitary mRNA.
- Radioactive labeling with [4,5-3H]leucine and [35S]methionine or [35S]cystine.
- Amino acid sequence analysis of the synthesized precursor.
Main Results:
- Successfully synthesized and labeled rat pre-prolactin.
- Identified a 29-amino acid N-terminal extension to the prolactin sequence.
- Determined the positions of leucine, methionine, and cysteine residues within the precursor sequence.
- Observed significant sequence similarity between rat pre-prolactin and other known protein precursors.
Conclusions:
- Rat pre-prolactin possesses a distinct N-terminal leader sequence of 29 amino acids.
- The identified precursor sequence shares homology with other secreted protein precursors, suggesting conserved processing mechanisms.